Stomach and back tightening at 30 weeks

Sharmain🌸

Hi everyone. I’ve been having this weird sensation for the past few weeks. It doesn’t happen every day. It feels like a tightening/squeezing sensation that starts in my belly and spreads to my lower back. It is not painful at all, just uncomfortable. It also only lasts a few seconds. Is this Braxton Hicks (even though it spreads to the back?) or is it contractions? Could it also just be baby just moving and stretching?